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SECTION 32 12 19.19
SECTION 32 12 19.19
OPEN-GRADED SURFACE COURSE (OGSC)
PART 1 GENERAL
| 1.1 | SECTION INCLUDES |
| A. | Materials and procedures for constructing OGSC. |
| 1.2 | RELATED SECTIONS |
| A. | Section 01452: Pavement Smoothness |
| B. | Section 02745: Asphalt Material |
| C. | Section 02746: Hydrated Lime |
| D. | Section 02748: Prime Coat/Tack Coat |
| 1.3 | REFERENCES |
| A. | AASHTO T 30: Mechanical Analysis of Extracted Aggregate |
| B. | AASHTO T 89: Determining the Liquid Limit of Soils |
| C. | AASHTO T 90: Determining the Plastic Limit and Plasticity Index of Soils |
| D. | AASHTO T 96: Resistance to Abrasion of Small Size Coarse Aggregate by Use of the Los Angeles Machine |
| E. | AASHTO T 104: Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate |
| F. | AASHTO T 112: Clay Lumps and Friable Particle in Aggregate |
| G. | AASHTO T 176: Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test |
| H. | AASHTO T 278: Surface Frictional Properties Using the British Pendulum Tester |
| I. | AASHTO T 279: Accelerated Polishing of Aggregates Using the British Wheel |
| J. | AASHTO T 304: Uncompacted Void Content of Fine Aggregate |
| K. | AASHTO T 308: Determining the Asphalt Binder Content of Hot-Mix Asphalt (HMA) by the Ignition Method |
| L. | AASHTO TP 61: Determining the Percentage of Fractured Particles in Coarse Aggregate |
| M. | UDOT Quality Management Plans |
| N. | UDOT Materials Manual of Instruction |
| O. | UDOT Minimum Sampling and Testing Requirements |
1.4 DEFINITIONS NOT USED
| 1.5 | SUBMITTALS |
| A. | Job mix gradation: at least 10 working days before paving. |
| 1. | Submit materials and documentation according to UDOT Materials Manual of Instruction, Section 954. |
| 2. | Aggregate suitability test results. |
| B. | Changes in job mix gradation: |
| 1. | Submit a written request for a change in a job-mix gradation. |
| 2. | Allow the COR five working days to review and approve the changes. |
| C. | Verification that Hydrated Lime meets the requirements of Section 32 12 16. |
| D. | Verification Asphalt Binder meets the requirements of Section 32 12 16. |
| 1.6 | ACCEPTANCE |
| A. | Acceptance sampling and testing of material as specified herein. |
| B. | A lot equals the number of tons placed during each production day. |
| 1. | A lot is evaluated on the test results of four samples, with the following exceptions: |
| a. | Compute disincentive using the test results from three samples if only three samples can be taken for the production day. |
| b. | Add the lot to the next day’s production if three random samples cannot be taken. |
| c. | Add the lot to the previous day’s production for the last day’s production if three random samples cannot be taken. |
| d. | The lot may be increased to include up to three production days when agreed upon in advance by both the Contractor and the COR and when less than 900 tons are anticipated per production day. |
| e. | Evaluate with the appropriate number of tests “n” in Table 4: |
| 2. | Asphalt Binder: COR will compute disincentive for asphalt binder content based on Table 1 using the single test result with the largest deviation from the target. AASHTO T 308. |
| a. | Apply incentive to the entire lot. |
| b. | Disincentive is applied only to the sublot defined as percentage of the lot represented by the test. |
| c. | Any lot that includes one or more sublots in disincentive is not eligible for incentive. |
Table 1: Asphalt Binder Content Pay Factors
| Pay Factor |
| Mean Absolute Deviation from Job Mix Formula |
3. Gradation: COR will compute incentive/disincentive for gradation is based on Percent Within Limits computation using Table 2. AASHTO T 30
Table 2: Aggregate Gradation Pay Factors
| Sieve Size |
| Pay Factor |
| Mean Absolute Deviation |
| 1/2 inch and larger |
| 1.00 |
| 0.0 to 5.6 |
| 4. | Any lot rejected based on either gradation or asphalt binder content will not be eligible for any incentive. |
| C. | Thickness |
| 1. | Verify the thickness with a depth probe and take corrective action if necessary. |
| a. | Minimum thickness: Plan depth minus ¼ inch. |
Table 3: Thickness Pay Factors
| Pay Factor |
| Thickness Variation, in Inches (ASTM D 3549) |
| 0.50 for excess material |
| Greater than + 0.25 |
| Reject |
| Greater than – 0.75 |
| D. | Smoothness |
| 1. | Lot size is 100 linear feet per lane or part thereof. A minimum of two tests per lot shall be taken in both the longitudinal and transverse directions. |
| 2. | Longitudinal requirement: 1/8 inch in 10 feet parallel to centerline. |
| 3. | Transverse requirement: 1/4 inch in 10 feet perpendicular to centerline except at cross section grade breaks. |
Table 4: Smoothness Pay Factors
| Pay Factor |
| Measurement Deviations, in Percent |
| E. | Submit an engineering analysis within one week if requesting that a rejected lot or sublot remain in place. |
| 1. | Include in the analysis: Data and engineering principles that indicate why the pavement should remain in place. |
| 2. | The COR will review the analysis for acceptance, denial, or revision within three working days. |
| 3. | Remove the rejected material from the project within 72 hours and replace it with an acceptable material if the request is denied. |
| 4. | Agree with COR on removal time period if rotomilling is required. |
| 5. | A Pay Factor of 0.50 applies if a rejected lot or sublot is allowed to remain in place. |
PART 2 PRODUCTS
| 2.1 | ASPHALT MATERIAL |
| A. | Refer to Section 32 12 16. |
| B. | Sampling procedure: UDOT Quality Management Plan - 509 Asphalt Binder. |
| 2.2 | HYDRATED LIME |
| A. | Meet the requirements of Section 32 12 16. |
| 2.3 | AGGREGATE MATERIALS |
| A. | Crusher processed virgin aggregate material consisting of crushed stone, gravel, or slag. |
| B. | Meet the following requirements, including Table5, to determine the acceptability of the aggregate. |
| 1. | Coarse aggregate: |
| a. | Retained on # 4 sieve. |
| 2. | Fine aggregate: |
| a. | Clean, hard grained, and angular. |
| b. | Passing the # 4 sieve. |
Table 5: Aggregate Properties
| Properties |
| Test Method |
| Test Requirement |
| One Fractured Face |
| AASHTO TP 61 |
| 95 percent min. |
| Two Fractured Face |
| AASHTO TP 61 |
| 90 percent min. |
| Fine Aggregate Angularity |
| AASHTO T 304 |
| 45 min. |
| L.A. Wear |
| AASHTO T 96 |
| Roads: 30% max. |
Airfield: 25% max.
| Sand Equivalent |
| AASHTO T 176 |
| 60 min. |
| Plasticity Index |
| AASHTO T 89 and T 90 |
| 0 |
| Polish Test |
| AASHTO T 278 & T 279 |
| 31 min. |
| Soundness (sodium sulfate) |
| AASHTO T 104 |
| 12 % max. loss with five cycles |
| Clay Lumps and Friable Particles |
| AASHTO T 112 |
| 2 % max. |
| 2.4 | JOB-MIX |
| A. | Obtain COR’s approval for job mix gradation: |
| 1. | Show definite single values for the percentage of aggregate passing each sieve based on the dry weight of aggregate. |
| 2. | Stay within the single value gradation limits of Table 6. |
| 3. | Incorporate minimum hydrated lime by dry weight of aggregate into all mixtures. Refer to Section 32 21 16: |
| a. | Method A, Lime Slurry incorporate 1 percent |
| b. | Method B, Lime Slurry Marination incorporate 1½ percent |
| B. | Binder Content |
| 1. | Indicate the binder content as a percent in the Job-Mix Formula. |
Table 6: Aggregate Gradation
Percent Passing by Dry Weight of Aggregate
½ inch ⅜ inch # 4 # 8 # 200 90 - 100 35 - 45 14 - 20 2 - 4
PART 3 EXECUTION
| 3.1 | MIX |
| A. | Mix until all particles are coated. |
| B. | Treat aggregate with hydrated lime according to the requirements of 32 12 16. |
| 1. | Verify lime slurry equipment is operating at all times when using Method A. |
| a. | Cease production if hydrated lime slurry treatment is interrupted. |
| b. | COR may require marination of the aggregate/hydrated lime mixture in the stockpile, Method B, if production continues without hydrated lime slurry treatment. |
| 3.2 | SURFACE PLACEMENT |
| A. | Apply the tack coat at a uniform rate. Refer to Section 32 12 10. |
| 1. | 0.10 gal/yd2 on new pavement. |
| 2. | 0.15 gal/yd2 on milled surfaces. |
| B. | Maintain a steady paver speed. |
| C. | Roll sufficiently to seat without fracturing aggregate. |
| D. | Bring all passes up even transversely at the end of each working day. |
| E. | Construct longitudinal joints within 6 inches of lane lines. |
| F. | Remove slick spots as directed by the COR. |
| 3.3 | LIMITATIONS |
| A. | Place between May 1 and September 15. |
| 1. | Obtain approval from the Government before placing OGSC after September 15. |
| B. | Place when the air temperature in the shade and the pavement surface temperature are above 60 degrees F and rising. |
| C. | Do not place if surface moisture is present. |
| D. | Do not place during rain or during other adverse weather conditions. |
| E. | Do not allow traffic on airfield OGSC for a minimum of 2 days after placement. |
END OF SECTION
OPEN-GRADED SURFACE COURSE Page 6
